I'm a Systems Reliability and DevOps engineer for Netdata Inc. When not working, I enjoy studying linguistics and history, playing video games, and cooking all kinds of international cuisine.
First off, you probably want to register a name, not purchase one. The two are technically different things. Registering a domain means you are acquiring rights to a currently unregistered domain name. Purchasing implies you are purchasing rights to an already registered name from the current registrant. In both cases, you will almost certainly have to pay recurring registration fees to maintain the registration (the exact cost and billing period depends on both the specific top-level domain and the registrar you use).
Second, you probably also will need DNS hosting to go with it, or at least the infrastructure and know-how to set up your own self-hosted DNS for the domain. Fortunately, most good registrars also provide an option for DNS hosting (sometimes free, sometimes as an add-on).
Most big cloud providers offer both domain registrar services and DNS hosting, they're probably your best bet short of a dedicated registrar option. I personally use Amazon Web Services, but I already had an account with them for other things and happen to like the flexibility that Route 53 (their DNS hosting service) provides. I've heard that Google Cloud Platform and CloudFlare are both good for this too, though I've not used either. I've heard essentially nothing about it, but I believe Microsoft Azure also offers domain registrar and DNS hosting services.
As has been mentioned elsewhere, avoid registering/purchasing the name bundled with other services. That bundling largely exists to foster vendor lock in, not to benefit the consumer. Note that I'm not talking about a case like AWS or GCP where you can buy individual services and have them billed all together on a single invoice, but stuff like website builders who offer a domain name for 'free' alongside the rest of their services.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
First off, you probably want to register a name, not purchase one. The two are technically different things. Registering a domain means you are acquiring rights to a currently unregistered domain name. Purchasing implies you are purchasing rights to an already registered name from the current registrant. In both cases, you will almost certainly have to pay recurring registration fees to maintain the registration (the exact cost and billing period depends on both the specific top-level domain and the registrar you use).
Second, you probably also will need DNS hosting to go with it, or at least the infrastructure and know-how to set up your own self-hosted DNS for the domain. Fortunately, most good registrars also provide an option for DNS hosting (sometimes free, sometimes as an add-on).
Most big cloud providers offer both domain registrar services and DNS hosting, they're probably your best bet short of a dedicated registrar option. I personally use Amazon Web Services, but I already had an account with them for other things and happen to like the flexibility that Route 53 (their DNS hosting service) provides. I've heard that Google Cloud Platform and CloudFlare are both good for this too, though I've not used either. I've heard essentially nothing about it, but I believe Microsoft Azure also offers domain registrar and DNS hosting services.
As has been mentioned elsewhere, avoid registering/purchasing the name bundled with other services. That bundling largely exists to foster vendor lock in, not to benefit the consumer. Note that I'm not talking about a case like AWS or GCP where you can buy individual services and have them billed all together on a single invoice, but stuff like website builders who offer a domain name for 'free' alongside the rest of their services.